内置十字型钢方钢管混凝土短柱压扭性能研究

Study on torsion behaviour of concrete⁃filled square steel tubular stub columns with internal cruciform steel

为研究内配十字型钢钢管混凝土柱在压扭作用下的受力性能,基于相关试验验证了有限元模型可靠性,并对比了不同加载路径时内配十字型钢方钢管混凝土柱的N/Nu-T/Tu相关曲线。重点对相同截面尺寸的钢管混凝土和内配型钢钢管混凝土在保持总含钢率相同和钢管壁厚相同的情况下分别进行受扭对比分析,随后对先压后扭作用时不同影响参数进行分析。结果表明先压后扭和先扭后压作用时内配型钢钢管混凝土的N/Nu-T/Tu相关曲线基本一致;保持构件截面尺寸和总含钢率相同时,钢管混凝土的抗扭性能优于内配型钢钢管混凝土,而保持构件截面尺寸和钢管壁厚相同时,内配型钢钢管混凝土的抗扭性能更好;各材料强度和型钢截面尺寸对压扭作用时的N/Nu-T/Tu相关曲线影响不显著,N/Nu-T/Tu相关曲线仅受轴压比的影响。基于参数分析建议了压扭作用时内配十字型钢方钢管混凝土构件承载力计算方程。

To study the mechanical performance of concrete⁃filled square steel tubular(CFST)columns with internal cruciform section steel under combined compression and torsion,the finite element model is verified based on existing tests,and then the N/Nu⁃T/Tu correlation curves of CFST with internal cruciform steel under different loading paths are compared.When the section size is same,the CFST columns and the CFST with internal cruciform steel are compared and analyzed respectively under the condition of maintaining the same total steel ratio or wall thickness of the steel tube,and then the influence of different parameters under the action of first compression and then torsion is analyzed.The results show that the N/Nu⁃T/Tu correlation curves of CFST columns with internal cruciform steel under the action of compression before torsion and torsion before compression are generally the same.Keeping the same section size of the members and total steel ratio,the torsional performance of CFST is better than that of CFST with internal cruciform steel,while keeping the same section size and wall thickness of steel tube,the torsional performance of CFST with internal cruciform steel is better.The strength of each material and the section size of section steel have slight effect on the N/Nu⁃T/Tu correlation curve under combined compression and torsion,and the N/Nu⁃T/Tu correlation curve is only affected by the axial load ratio.Based on the parameter analysis,the calculation equation of bearing capacity for square CFST with internal cruciform section steel under compression and torsion is proposed.